The 3 feet exon of the human c-myc oncogene was cloned in pBR322. This probe detected two Eco RI rearranged c-myc gene fragments (3.6 and 2.4 kb) in Raji (Burkitt's lymphoma) cells. The two DNA fragments were isolated from Raji cell DNA and cloned in lambda phage. Restriction enzyme analysis revealed that the 3.6-kb fragment carried the entire 5 feet and 3 feet c-myc exons, while the 2.4-kb fragment contained only part of the 3 feet c-myc exon. Neither DNA fragment contained immunoglobulin sequences.